Door latch mechanism



Jan. 6, 1953 H. w. SANFOR DOOR LATCH.MECI-IANISM Original Filed April 16, 1945 Patented Jan. 6, 1953 DOOR LAT-CH MECHANISM HughW. Sanford, Knoxville, Tenn, assignor to The Sanford Investment Company, Wilmington, Del., a. corporation of Delaware Original application April 16, 1945, Serial No. 588,577; Divided and this application April 8, 1949, Serial'No. 86,301

12 Claims. 7 1

This invention relates to improvements in door latch mechanisms, particularly for mine cars and other conveying devices havingdropxbottom doors for the discharge of lading therefrom.

This application is a division of my prior application for Door Latch Mechanisms, Ser.. No. 538,577, filed April 16, 1945. It is also an improvement on the latch devices set forth in my prior application, Ser. No. 432,341, filed February 25, 1942, now Patent No. 2,399,708, granted May 7, 1946.

In the door latch mechanisms set forth in my prior patent, the latches that support the free edge of the door were mounted at transversely spaced points on opposite sides of the longitudinal center line of the car in positions to engage and support thefreeedge of the door. In that application and patent the latches were adapted to be engaged directly bythe tripping device mounted in the trackway, to release the same from engaged position. The latches were either fixed to the cross-shaft or freethereof.

An object of this invention is to improve the construction of the latch mechanism, in which one or bothlatchesis mounted on the cross shaft for freedom of movement with respect thereto in one direction, except as such resistance may be offeredto the movement by friction or a spring, but in which movement of the shaft willoperate the latch to release it from the door. Therefore, the latch. has lost motionv with respect to the shaft, so as to be free to move only in one direction with respect thereto without moving the shaft or-the other latch mounted thereon. However, when the rock shaft itself; is rotated, both latch hooks must move from their door supporting positions into their door releasing positions.

A further object of the invention is to provide for the locking of the latch hook against releasingl movement wherebyto make it impossible for the doors to drop when. the car is in transit. This is-desirable particularly when workmen are riding in the cars, asmay be done, occasionally in transporting jworkmen' into and out of the mine.

Ihave provided alsupporting member. for the latch book which "is rotatable with. the hook in moving to a released position, and hasv means for locking this supportingmember against turning movement so as to hold the hook against releasing action, wherebyv the latch hook will be retained in its latched'position.

The invention .is shown applied to. a mine car as the.preferredapplicationthereof, in the accompanying drawings vin which: v

Fig, v.1 is a side: elevation 'of "the mine car and latch-tri pingmechanism;

Fig. 2 is a side elevation, partly in section, show ing the mounting ofvthe latchv hookon the rockshaft;

Fig. 3 is a detailed side elevation of a portion of the car, showing the cross shaft lock mechanism;

Fig. 4 is a transverse section ther'ethro'ugh on the lined-4 in Fig. 3, showing the device in its locked positions;

Fig. 5 is a similar View showing the'lock means in released position; and

Fig. 6 is a partial top plan'view of the car showing the mounting of the latches.

This invention is shown as applied to a mine car of the general type set forth in my prior patent, No. 2,001,471,,granted May 14", 1935, adapted for conveying coal or other loose lading from a receiving point to a tipple or other point of discharge. The mine car isshown to be' of the 4-Wheel type, having three drop bottom doors interconnected for release in one-two-three order. This application of the invention is used, however, merely for the purpose of illustration, and it is evident that the subject matter of this invention may be applied to other types of cars, vehicles, and drop bottom conveyors'in general, wherever it may be desirable'to release bottom doors for dropping, in which theprinciples of this invention may be applicable.

The general structure of the car illustrated comprises a car body formed of side and. end walls l and 2, rigid-1y secured together, the side walls I rising from a pair of oppositelydisposed side sills 3, connectedtogether at the ends'of the car by means of combined end-sills and bump= ers, designated generally at 4 and supportedby bumper plates 5. The side and end-sills 3 and t comprise the frame structure of the car for supporting the lading body thereof, and between which is a bottom opening designed generally for discharge of the lading therethrough.

The car is supported upon wheelsB and axles 1 connected with the side sills 3t The'wheels 6 are adapted to-travel on a track formed by a pair of laterally spaced rails indicated generally at R. I I

The car is shown of the character provided with three drop bottom doors adaptedfor' discharge in one-two-three order from front'torear of the ear. These doors-aredesignatedrespectively by the numerals8, 9 andl 0.- The forward door 8 is pivotally supportedatitsfon ward edge on a hinge rod ll", while each of the middle and rearward'doors Band It! is slidably and pivotally mounted one hingerod l2. extendmg between the frame" structures at opposite sides of the drop bottom opening. Any other suitable door construction or arrangement may be used as desired.

The extreme forward edge of each of said doors 9 and [0, when in closed or latched position, projects laterally from the hinge rod [2, and is adapted to support the free edge of the next forward door. Then upon release of the rearward door, it may drop sufliciently to drag and move bodily rearward, thereby releasing the free edge of the middle door which will likewise drop and release the free edge of the forward door. This occurs usually just before the car reaches the tipple or bin, and permits dropping of the forward door in the bin for discharge of the lading thereon, as soon as room enough is provided in the bin therebeneath. The other doors drop in succession during the continued forward movement of the car over the bin or tipple in one-two-three order from front to rear of the car.

After dumping in passing over the bin or tipple, the doors are adapted to be closed by the usual door-closing rails located in the track. The doors may have indentations [3 in the under faces thereof to ride on the door-closing rails, which indentations would extend transversely of the doors throughout substantial portions of the width thereof. The doors are thus moved successively about their hinge rods to their closed positions, and the middle and rearward doors are pushed forward into wedging relation with the next forward door, adapted to be latched in closed position.

The foregoing car structure, to which this invention is shown applied as hereinafter described, is set forth more in detail in my prior patents, No. 2,001,471, May 14, 1935, and No. 2,036,644, April '7, 1936, to which reference is made for a more complete illustration of the structure there- As shown in Figs. 1 and 2, provision is made for latching the free edge of the rearward door in closed position, thereby holding the several doors closed, to retain the lading in the car until the latching means is released for dumping. For this purpose, I have provided on the free edge of the rearward door [0, one or more supporting trunnions I4, one for each latch of said door. I prefer to use a pair of latches, each designated generally by the numeral [5 and spaced apart transversely of the car, symmetrically with respect to the longitudinal center of the car. The latches l5 are pivotally mounted on a cross shaft or rockshaft l1 supported by brackets l8 secured to the adjacent bumper plate 5 of the car. Each of the latches I5 is preferably so constructed, or spring-pressed, as to be disposed normally in its door supporting position, or to return thereto automatically when disengaged for release of the lading.

Each of the latches I5 is provided with a seat l9 at the forward face thereof in position to receive the end of the adjacent trunnion I4 attached to the free edge of the rearward door I0. Each of the latches I5 is provided, preferably, with a lateral pin attached thereto and projecting through a slot in the adjacent portion of the end-sill plate 5.

The latches l5 are interposed between the free edge of the rearward door I0 and the adjacent end-sill structure 4, underneath a deflector plate secured to the adjacent end wall 2. The latches 15 are so constructed and arranged that they are disposed wholly above the lower edges of the latches to maintain these in proper operative positions.

Each latch I5 is so mounted in protected position between the door l0 and the bumper 4 that a tripping space is provided between said door and the latch l5 in latched position for entry of a tripping arm therebetween.

While any suit-able form of tripping mechanism may be used, as desired, for releasing the latches l5, the form shown in Fig. 1 includes tripping mechanism generally of the form set forth in my prior application, Ser. No. 588,577, wherein a tripping arm 3! is adapted to engage and release each of the latch hooks l5, normally being urged into engagement therewith by a spring 42 connected therewith. The tripping arm is of the hook type as shown in said application, and therefore the latch hook I5 is provided with a notch 25 in the forward face thereof in position for engagement by the hook of the tripping arm. A contact mem-- ber 32 is connected with the tripping arm 3! in position to follow along the under surface of the car in bearing engagement with the bottoms of the doors, to raise and lower the tripping arm as the car moves thereover, substantially as described more in detail in my application above mentioned.

It may be desirable under some circumstances to release the latches manually, or by external means, to open the bottom doors and dump the l-ading, as when the car is standing still on the trackway. This may be done by extending the latch supporting shaft through one of the side flare plates of the car body to a point externally thereof, as shown for instance in Fig. 4. The shaft 11 that supports the latches is preferably round between the side wall flare plates 1, but at least one end of this shaft I1 is preferably extended through the flare plate I to a point externally of the confines of the car body. At this point, the shaft extends through a bearing box 51 secured to the inner face of the flare plate I at a point where it is protected beneath the deflector plate, as will be evident from Fig. 4. The bearing box 51 has its outer end so constructed as to conform to the inner face of the flare plate I, as shown in Fig. 3, and may be welded or riveted to the flare plate and form a journal for the end of the cross shaft but at a point where it is out of contact with the lading.

The projecting end of the shaft I1 is shown as square in cross section, as indicated at 58, although the shape thereof may be of any desired form. This squared end is adapted to receive an ordinary hand crank or other element which may be applied thereto for rotating the shaft l! in counter-clockwise direction to cause release of the latches [5 when this may be desired, at a point externally of the car body. Thus the door may be unlatched manually without movement over the tripping mechanism, as is desired frequently.

The latches I5 are loose on the shaft I! for individual respective actuation as described above. I have provided some lost motion between each latch l5 and the shaft 11, as shown in Fig. 2. The hub of the hook is journaled on the shaft but is provided with slots 55 therein receiving a locking pii1-- 561 which extends through the slots and throughthe cros's shaft H to secureeach'of the men are riding in thecar; for which purpose I have provided a locking device as shown in Figs. 3 4 and 5. This is used in connection with the squaredfe'nd'i8 of'the cross shaft I! at a'point externallyof' the side flare plate I, and the, lock-' ing device is-preferably supported by the flare plate.

In the form shown, the locking device is carried b'y a bracket 59-we1ded or otherwise rigidly fixedfto' the outer-face of the flare plate and having a stub' shaft ourna'led' therein. One end'of the'stub shaft GEiha-s fixed thereto a locking member 6| disposed on one side of the'bracket 59 in position'to beturned up between the bracket 59 and'the' adjacent face of the squared endl58of the shaft l-l to hold the shaft against turning movement; The'opposite end ofthe stub shaft 60 has fixed thereto-a crank member 62 carrying a handle'fifi thereonfolr manual shiftingof the looking memb er'fi'l. This crank 62 should be considerably heavier than the locking member 6|, so that normally it will tend to rotate downward to the position shown in Fig. 4, holding the locking member. in its locking position. The parts are thus disposed when the eerie in transit audit-is; not desire'dto actuatethe-latches for release of the'doors. v 7

When the car gets to the dumping bin, or'it is desired to release the locking means, it is necessary merely to rotate the crank 62 to the position shown in Fig. 5, where itwill be supported by a stop 64, thus holding the locking member 6| out of engagement with" the squared end 58 of the cross shaft IT. This will leave the shaft free for turning movement by the tripping mechanism, allowing the dumping of the lading automatically in the manner described above. It will be evident that the-locking mechanism may be used when desiredand yet it may be retained in operative position when not required, allowing dumping of the car automatically.

The locking mechanism and squared. end of the shaft may be protected by an extended portion 65 on the bumper structure, shown in Fig. 4, against injury thereto.

The latch hooks [5 are supported on the rock shaft H for freedom of movement in one direction with respect thereto, as described above. The pin 56 not only prevents movement of each latch hook in one direction with respect to the shaft, but also prevents movement of the latch lengthwise of the shaft. The forward movement of the latch hook with respect to the shaft I! is substantially as shown in Fig. 2, but the rearward movement is free except for the resisting action of the coil spring bearing on the latch until the back face of the latch hook strikes the end-sill plate 5. Thus the latch hook is relatively free of the rockshaft I! so as to "be capable of moving backward independently thereof to provide means by which, if one latch hook is struck by an object on the track and is forced backward into its door releasing position, the other latch hook will not be moved backward in the; same 1 manner butwill continue; to support the of the" door" under' such circumstances;-

Itis also arranged; owever. so that when'th'emoved acoldf'itally' "to its remased position, and

yet both latcheswill be -'moved'to door releasing positions when the rocksha'ft' itself is moved.

While the invention has been illustrated and described in one embodiment, it is recognized that variations and changes may be made therein without departing from the invention; except as specifiedin the claims.

I'claim':

1. ma dumpingconveyanoehaving a lading body with a drop bottom door anda pluralityof latch hooks forsuppOrting an edge of'the' door. a; cross shaft mounted on theconveyance and supportingthe hooks thereon, means mounting the hooks on the cross shaft for freedom of movement of thehooks with respect thereto in one direction and for'positive movement of the hooks upon rotation of the-cross shaft in one direction. and resilient'means acting onthe hooks normally tending to turn said hooks in one direction there 2. In a dumping conveyance having a lading body with a 'drop bottonr door and a plurality of latch hooks for'supportingan edge of'the'door, a cross shaft mounted on the conveyance and supporting the hooks thereon, means for providing lost motion-between the hooks and said shaft,

I and resilientmeans acting on the hooks normally tending to turn said hooks in-one direction there- 3. In a dumping conveyance having alading body with a drop bottom door and a plurality of latch hooks for supporting an edge of said door, a cross shaft mounted'onthe conveyance and supporting thehooks' thereon, means connected with the cross shaft for rotating said shaft, means for securing' the hooks on the shaft for movement of the hooks to released positions upon rotation of the shaft in one direction, means connecting the hooks with the shaft for freedom of movementof the hooks relative thereto in one direction without movement of the shaft, and resilient means acting on the hooks normally tending to turn said hooks in one direction there- 4. In a dumping conveyance having a lading body with a drop bottom door and a plurality of latch hooks for supporting an edge of said door, a cross shaft mounted on the conveyance and supporting the hooks thereon, means connected with the cross shaft for rotating said shaft, means for securing the hooks on the shaft for movement of the hooks to released positions upon rotation of the shaft in one direction, and a pin and slot connection between each of the hooks and shaft for freedom of movement of the hooks with respect to the shaft in one direction.

5. In a dumping conveyance having a lading \body with a drop bottom door and a plurality of latch hooks for supporting an edge of the door. a cross shaft mounted on the conveyance and supporting the hooks thereon, each of said latch hooks having a hub portion mounted on the cross shaft and having a slot therein, and a pin fixed to the cross shaft in the slot for providing a lost motion connection between each said latch hook and the shaft.

6. In a dumping conveyance including a lading I body havingra drop bottom door and a latch for supporting the door and movable to release the door for dumping, a cross shaft supporting the latch and having an end portion projecting through a side wall of the lading body, a bearing box fixed to said side wall and journaling said end portion of the shaft therein, said shaft having a handle-receiving portion thereon externally of said side wall in position for engagement to release the latch manually.

7. In a dumping conveyance including a lading body having a drop bottom door and a latch for supporting the door and movable to release the door for dumping, a cross shaft supporting the latch and having an end portion projecting through a side wall of the lading body, a bearing box fixed to said side wall and journaling' said end portion of the shaft therein, said shaft-having a flattened portion externally of said side wall, and lock means mounted on the conveyance in position to engage said flattened portion and to hold the shaft against rotation.

8. In a dumping conveyance including a lading body having a drop bottom door and a latch for supporting thed'oor'and movable to release the door for dumping, a cross shaft supporting the latch and having an end portion projecting through a side Wall of the lading body, a bearing box fixed to said side wall and journaling said end portion of the shaft therein, said shaft having a flattened portionexternally of said side wall, and lock means mounted-on the conveyance in position to engage said fiattenedportion and to hold the shaft against rotation, said lock means including a locking member pivotally mounted on the conveyance for swinging movement into and out of engagement with the flattened portion of the shaft, and a crank member connected with the locking member for swinging said locking member.

9. In a dumping conveyance including a lacling body having a drop bottom door and a latch for supporting the door and movable to release the door for dumping, a cross shaft supporting the latch and having an end portion projecting externally of a side wall of the lading body, said shaft having a flattened portion externally of said side wall, and lock means mounted on the conveyance in position to engage said flattened portion andto hold the shaft against rotation.

10. In a dumping conveyance including a lading body having a drop bottom door and a latch for 8. supporting the door and movable to release the door for dumping, a cross shaft supporting the latch and having an end portion projecting externally of a side wall of the lading body, said shaft having a flattened portion externally of said side wall, and lock means mounted on the conveyance in position to engage said flattened portion and to hold the shaft against rotation, said lock means including a locking member pivotally mounted on the conveyance for swinging movement into and out of engagement with the flattened portion of the shaft, and a crank member connected with the locking member for swinging said locking member.

11. In a dumping conveyance having a lading body witha drop bottom door and a plurality of latch hooks for supporting an edge of said door, a cross shaft mounted on the conveyance and supporting the hooks thereon, means connected with the cross shaft for rotatin said shaft, means for securing the hooks on the shaft for movement of the hooks to released positions upon rotation of the shaft in one direction, a pin and slot connection between the hooks and shaft for freedom of movement of the hooks with respect to the shaft in one direction, and a spring bearing against each hook tending to hold the hook in one extreme position with the pin at one end of the slot.

12. In a dumping conveyance having a lading body with a drop bottom door and a plurality of latch hooks for supporting an edge of the door, a cross shaft mounted on the conveyance and supporting the hooks thereon, each of said latch hooks having a hub portion mounted on the cross shaft and having a slot therein, a pin fixed to the cross shaft in the slot for providing a lost motion connection between each said latch hook and the shaft, and a spring bearing against each hook tending to hold the hook in one extreme position with the pin at one end of the slot.

HUGH W. SANFORD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Sheesley Sept. 20, 1949 

